Sunday, 15 March 2015

Mini 3G 150M A5-V11 Router (internals/UART)

There's very little information in the product description, but for my 7 quid I ended up with a board known as "A5-V11", which has a RT5350, 4M SPI flash, 32M RAM. It is supported by openwrt (here) but the current bleeding edge with the defaults set is too big. It fits if you drop the IPv6 related packages.

It's already well documented so there isn't any need for much more here. Worth noting is that a standard SOIC clip (i.e. Pomona-style) won't quite make contact due to the position of the big capacitor in the middle. The micro USB port is only used for power... so for future experiments I wired the UART to it following the same pinout as Mediatek stuff. A resistor is required on RX or it won't boot (value not critical, also works fine with 330 ohm).

10 comments:

Is there an OpenWRT build that allows me to plug in a USB sound module into this device and somehow emulate like the USB sound module was plugged into my windows machine? In other words, I want to play music over the LAN cable from my Windows PC to my stereo system in another part of the house. Thanks!

Sure - there are hundreds of different USB-UART cables, I'm sure some are labelled the opposite way around. My annotated photo shows the direction relative to the SoC, as in "TX" is the router transmitting data out, so should be connected to "RX" of a correctly labelled UART.

Hmm, I think I know why Rx and Tx is swapped on my cable. I own the same cable like the one you modded in this post: http://www.stevenhoneyman.co.uk/2014/11/mtk-mediatek-debug-cable.html. You mentioned there, that you soldered the green and white cables the wrong way round (I assume you swapped them aferwards), but on my unmodded cable these are exactly the same order like in the picture of your post.

This UART interface is pretty useful! In the end I was able to unbrick my router :) So thank you for this blog post!

Hey :)I created a portable wireless music system with webradio, dlna/upnp server and dlna/upnp renderer with this little router!All in all this project costs about 25€.Read more:http://board.nwrk.biz/viewtopic.php?id=125